I wrote about this dessert back in July, when I reviewed Calliope. But since then, after dinners in the East Village, I’ve found myself drawn back to Eric Korsh and Ginevra Iverson’s bistro for a late-night coffee and a hot buttery bun, split at the table, poured over with rum, and dolloped with softly whipped cream. Glorious. Pastry chef Shuna Fish Lydon, formerly of Peels, makes the classic French dish shine.